Mr Egeland expressed shock that "block after block" of buildings had been levelled.

"It makes it a violation of humanitarian law," he said.

Mr Egeland appealed for both sides to put a halt to attacks, and urged Israel to allow the secure passage of aid.

Amid growing concerns about the hundreds of thousands of civilians displaced by the bombing, Israel has eased some restrictions on Lebanon's blockaded ports to allow aid into the country.

Envoys to press Israel

Three European envoys are to hold talks with Israel on Sunday, ahead of a visit by the US Secretary of State.

Israel has urged the US to hasten the delivery of weapons

Israeli officials are scheduled to meet German Foreign Minister Frank-Walter Steinmeier and French Foreign Minister Philippe Douste-Blazy, who has warned of a spiral of violence.

UK Foreign Office Minister Kim Howells will also travel to Israel for talks, having already accused its government of imposing a collective punishment on Lebanon in its 12-day campaign against Hezbollah fighters.

And US Secretary of State Condoleezza Rice is travelling to the Middle East on Sunday.

Ground clashes

Along with southern Beirut and Sidon, there were Israeli bomb attacks on the Bekaa valley and explosions were heard near the southern city of Tyre on Sunday.

Israel says its forces have driven Hezbollah guerrillas out of the hilltop village of Maroun al-Ras close to the Israel border, where six Israeli commandos were killed earlier this week.